- Palladium-Catalyzed Thiomethylation via a Three-Component Cross-Coupling Strategy
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In this report, the combination of masked inorganic sulfur and dimethyl carbonate was designed to achieve thiomethylated cross coupling of aryl chlorides. Remarkably, this powerful strategy realized thiomethylation of nucleosides bearing unprotected ribose, chloride-containing pharmaceuticals with late-stage coupling, and herbicides possessing multiple heteroatoms and steric hindrance. Moreover, this protocol is practically amenable to multigram-scale synthesis with a lower catalysis loading and a higher yield.
- Wang, Ming,Qiao, Zongjun,Zhao, Jiaoyan,Jiang, Xuefeng
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supporting information
p. 6193 - 6197
(2018/09/25)
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- Methyl aryl thioether compound, and synthetic method and applications thereof
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The invention discloses a methyl aryl thioether compound represented by formula 2, and a synthetic method and applications thereof. According to the synthetic method, in a reaction solvent, an aryl halide or an aromatic halide, dimethyl carbonate, and potassium thioacetate are taken as reaction raw materials, reaction is carried out in the presence of metal palladium catalyst under the action of a ligand and an alkali so as to obtain the methyl aryl thioether compound. The reaction conditions of the synthetic method are mild; the raw materials are cheap and easily available; reaction operation is simple; yield is relatively high. The methyl aryl thioether compound can be used for providing skeleton structures for the synthesis of a plurality of natural products and medicines, and can be widely applied in industrialized large-scale production.
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Paragraph 0152; 0153; 0154
(2017/07/21)
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- High-throughput five minute microwave accelerated glycosylation approach to the synthesis of nucleoside libraries
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The Vorbrueggen glycosylation reaction was adapted into a one-step 5 min/130 °C microwave assisted reaction. Triethanolamine in acetontrile containing 2% water was determined to be optimal for the neutralization of trimethylsilyl inflate allowing for direct MPLC purification of the reaction mixture. When coupled with a NH3/methanol deprotection reaction, a high-throughput method of nucleoside library synthesis was enabled. The method was demonstrated by examining the ribosylation of 48 nitrogen containing heteroaromatic bases that included 25 purines, four pyrazolopyrimidines, two 8-azapurines, one 2-azapurine, two imidazopyridines, two benzimidazoles, three imidazoles, three 1,2,4-triazoles, two pyrimidines, two 3-deazapyrimidines, one quinazolinedione, and one alloxazine. Of these, 32 yielded single regioisomer products, and six resulted in separable mixtures. Seven examples provided inseparable regioisomer mixtures of -two to three compounds (16 nucleosides), and three examples failed to yield isolable products. For the 45 single isomers isolated, the average two-step overall yield ± SD was 26 ± 16%, and the average purity ± SD was 95 ± 6%. A total of 58 different nucleosides were prepared of which 15 had not previously been accessed directly from glycosylation/deprotection of a readily available base.
- Bookser, Brett C.,Raffaele, Nicholas B.
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p. 173 - 179
(2007/10/03)
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- Anti-HCV nucleoside derivatives
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The present invention comprises novel and known purine and pyrimidine nucleoside derivatives which have been discovered to be active against hepatitis C virus (HCV). The use of these derivatives for the treatment of HCV infection is claimed as are the novel nucleoside derivatives disclosed herein.
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- Methylation of mercaptopurine, thioguanine, and their nucleotide metabolites by heterologously expressed human thiopurine S-methyltransferase
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Thiopurine S-methyltransferase (TPMT), a cytosolic enzyme that exhibits genetic polymorphism, catalyzes S-methylation of mercaptopurine (MP) and thioguanine (TG), yielding S-methylated nucleobases that are inactive, whereas S-methylated nucleotides of these thiopurines are cytotoxic. A yeast- based heterologous expression system was therefore used to characterize human TPMT-catalyzed methylation of MP, TG, and their principal nucleotide metabolites [thioinosine monophosphate (TIMP) and thioguanosine monophosphate (TGMP), respectively]. MP, TG, TIMP, and TGMP were all substrates for human TPMT, exhibiting similar Michaelis-Menten kinetic parameters (K(m), 10.6- 27.1 μM; V(max), 31-59 nmol/min/mg of TPMT). Consistent with these kinetic parameters, human leukemia cells (CEM) incubated for 24 hr with 10 μM MP or TG accumulated significantly higher (2.3-fold, p = 0.01) concentrations of methyl-TIMP after MP incubation than methyl-TGMP after TG incubation, due to the 2.7-fold higher concentration of TIMP after MP incubation, compared with TG nucleotides (TGN) after TG incubation. Moreover, intracellular accumulation of TGN was 2.5-fold greater after TG incubation than after MP incubation (p = 0.01). These data establish that MP, TG, and their principal nucleotide metabolites are comparable substrates for polymorphic TPMT, and they demonstrate significant differences in the accumulation of active TGN and methylated nucleotides when leukemia cells are treated with MP versus TG.
- Krynetski, Eugene Y.,Krynetskaia, Natalia F.,Yanishevski, Yuri,Evans, William E.
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p. 1141 - 1147
(2007/10/03)
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- Nucleic acid related compounds. 86. Nucleophilic functionalization of adenine, adenosine, tubercidin, and formycin derivatives via elaboration of the heterocyclic amino group into a readily displaced 1,2,4-triazol-4-yl substituent
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Treatment of 9-methyladenine and hydroxyl-protected derivatives of adenosine and 2′-deoxyadenosine with 1,2-bis[(dimethylamino)methylene]hydrazine and/or its dihydrochloride at elevated temperatures in appropriate solvents resulted in elaboration of the 6-amino group into a 6-(1,2,4-triazol-4-yl) substituent in excellent yields. Analogous functionalization of the amino groups of tubercidin {4-amino-7-(β-D-ribofuranosyl)pyrrolo[2,3-d]-pyrimidine} and formycin {7-amino-3-(β-D-ribofuranosyl)pyrazolo[4,3-d]pyrimidine} gave the respective 4- and 7-(1,2,4-triazol-4-yl) derivatives. Nucleophilic replacement of the triazole moiety gave the respective 6-, 4-, and 7-substituted purine, pyrrolo[2,3-d]pyrimidine, and pyrazolo[4,3-d]pyrimidine products. This first general method for "direct" nucleophilic replacement of an amino group on these nitrogen heterocycles also provides a new class of compounds for potential postsynthetic modifications after incorporation into oligonucleotides.
- Miles, Robert W.,Samano, Vicente,Robins, Morris J.
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p. 5951 - 5957
(2007/10/02)
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- Photoinduced Alkylthiolation of Halogenated Purine Nucleosides
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A new highly efficient methodology for the synthesis of biologically important methylmercaptopurine nucleosides is described.The approach represents a substantial improvement over earlier reported methods for this class of compounds.
- Nair, Vasu,Young, David A.
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p. 450 - 453
(2007/10/02)
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- 6-Substituted purine 3',5'-cyclic nucleotides
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Described herein are novel 6-alkylthio and 6-arylalkylthio purine 3',5' cyclic nucleotides variously exhibiting adenyl cyclase and (in animal studies) tumor inhibitory properties, interferon potentiation, antiviral activity, and the ability to activate adenosine 3',5'-cyclic phosphate-dependent protein kinase while enjoying resistance to phosphodiesterase hydrolysis superior to that of its naturally occuring analog. The compounds are obtained by alkylation of the corresponding 6-thio nucleotide, which is in turn provided by a novel synthetic route
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